PIPE FLOW SOFTWARE ... Calculate ... Simulate ... Communicate

      

        

           Fluid Flow
            (Home) 
          | 
           About
            Us 
          | 
           Navigate
            this site 
           | 
           Contact Us 
        

      

 


SoftwareSelector:


      by
      application

      by
      name 


      Download
      an evaluation copy of our software

      


      Software Support

      Software
      Users

      Licensing
      


      Fluid
      Flow Design and Consulting



      		  
      

        

           FLUIDFLOW3 
           2-Phase (multiphase)
            gas/liquid simulation 
          Previous 
           Contents 
          Next
           
        

      


      

        

          
            


            2-PHASE MODULE

            Gas / Liquid Multiphase Calculations

            

          		
        

      


      
The calculation of frictional
      pressure loss for two phase gas-liquid flow is complex. The coexistent
      flow of two phases complicates the theoretical and empirical
      approaches which are available; this means that a complete analytical
      solution is not possible. After 60 years of extensive research
      it is rare to find two correlations with exact predictions. In
      an effort to overcome these shortcomings the 

      FluidFlow3: 2-Phase module provides six choices of correlations
      that represent some of the most successful approaches to this
      complex problem.


      
Which equation?


      
Until recently, the "literature
      consensus" indicated that a mechanistic approach could be
      used for all gas liquid ratios and all pipe inclinations. Great
      in theory, but in practice, you need to make simplifying assumptions
      to solve/close the equations. FluidFlow3 implements a simple
      mechanistic model according to Beggs-Brill. There are more complex
      mechanistic models in the literature (Shoham or Aziz - in a future
      release), but these are not trivial to implement successfully.


      
Recently, the "literature
      consensus" appears to agree that mechanistic modelling has
      gone as far as it can go and researchers are now favouring a
      drift flux approach. FluidFlow3 implements also this type of
      relationship, but this model is best suited for vertical and
      inclined pipes.


      
As a general purpose model for
      single component two phase flow the Muller Steinberg Heck relationship
      is considered to be the most accurate, but the method looses
      accuracy at high vapour qualities.


      
Perhaps the most comprehensive
      literature summary was carried out by Whalley. The recommendations
      of this study use gas/liquid ratios and gas/liquid viscosities
      to determine the best correlation to use. This is the default
      calculation method used by FluidFlow3.


      
If you are dealing with steam/condensate
      systems the recommendation is to use either use Muller Steinberg
      Heck or Whalley.


      
Examples



      FluidFlow3: 2-Phase is
      best illustrated by the following examples:


      
    
        
  • Example
        1: Air water two phase
        model. Constant quality.
        
  • Example
        2: Refrigerant system.
        Changing quality.
      


      
References used in the developoment
      of the FluidFlow3: 2-Phase module:


      
1 Mechanistic Modeling of Gas-Liquid
      Two-Phase Flow in Pipes - O. Shoham ISBN 978 1 55563 107 9

      2 Fluid Flow Handbook - J. Saleh - ISBN 0 07 136372 6

      3 A Basic Approach to Wellbore Two Phase Flow Modelling - AR
      Hasan, CS Kabir and M Sayarpour - SPE 109868

      4 Process Heat Transfer Principles and Applications - R Serth
      - ISBN 978 0 12 373588 1

      5 Stromung und Druckverlust - Walter Wagner - ISBN 3 8023 1879
      X

      6 Two-Phase Flow in Complex Systems - S Levy ISBN 0 471 32967
      3

      8 Friedel L. Improved friction pressure drop correlations for
      horizontal and vertical two phase pipe flow. Ispra European Two
      Phase Flow Group meet, Paper F2 (1979).

      9 A Simple Mechanistic Model for Void Fraction and Pressure Gradient
      Prediction in Vertical and Inclined Gas/Liquid Flow Khasanov
      et al.



      

        

           FLUIDFLOW3 
           2-Phase (multiphase)
            gas/liquid simulation 
          Previous 
           Contents 
          Next
           
        

      

        

           Fluid Flow (Home) 
          | 
           About Us 
          | 
           Navigate this site 
           | 
           Contact Us 
           | 
          Top 
        

      


Copyright  Disclaimer  Conditions
      of Use of Accutech Software